As the level of automation has increased in mass production facilities, and the speed of welding operations has increased, it has become increasingly important for management personnel to monitor and control welding parameters and processes to assure consistent and proper joining of materials, and to ensure that completed welds fall within predetermined quality parameters.
To provide a high level of consistency in welds, semi-automatic, automatic, and robotic welding processes therefore typically include welding programs or procedures that are preprogrammed for specific operations. These programs, in theory, should provide consistent and repeatable welds, irrespective of the experience level of the user. Experience has shown, however, that even in highly automated applications, welding parameters can and do vary after long periods of use, and in different environmental conditions. These variations can be caused by a number of factors, including, for example, variations in the parts to be welded, variations in motor and wire feed speed control over periods of use, variations in gas flow over time, and variations in the distance between a welding tip and the workpiece.
Increasingly, moreover, welding personnel on the factory floor are relatively inexperienced and insufficiently trained to properly identify and correct for these problems. In addition to providing predetermined welding procedures, therefore, it is also important for management personnel to monitor weld and operator performance. Monitoring of the weld allows management personnel to analyze the welding process, identify problems, and make corrections before significant down time or waste of material occurs.
To meet these needs, arc monitoring devices have been developed. These devices are typically stand-alone units, connected external to the welding power supply, and which include sensors for monitoring welding parameters, such as current, voltage, and wire feed speed. These devices typically provide a visual or audible signal when a welding feedback parameter is outside of a predetermined range, providing a signal to the operator or his or her supervisor that a fault has occurred. Monitoring and alarm data can be used to train personnel by providing an alarm signal when a weld has veered outside of accepted parameters. This data can also be used to make corrections during the welding process, and can be stored for analysis.
While providing a valuable function, these devices, however, add significantly to the complexity and expense of a welding cell installation, require additional external wiring for the sensors, and increase the overall size or footprint of the cell itself. Furthermore, because these devices require external sensors, often times, they do not provide sufficiently accurate readings of actual weld parameters, and they cannot provide all of the data necessary for properly monitoring a weld.
Additionally, because these devices are external to the welding system itself, they cannot monitor wire feed motor power or other parameters that are useful in analyzing both equipment failure and failures or deterioration of consumables, such as contact tips, or in other components such as wire feed liners and drive rolls. Furthermore, these devices cannot be used to monitor or to adjust the welding commands during a welding process, and therefore are not optimized for training purposes, or for teaching operators to correct for problems encountered during a weld, and cannot correct for poor selection of welding commands. The present invention addresses these problems.